Over the last few decades, public outcries against pollution have brought ... ...

Over the last few decades, public outcries against pollution have brought about stricter regulations of emissions. The cities that had the most polluted air 30 years ago now have greatly improved air quality. This would not have happened without these stricter regulations. Which one of the following can be properly inferred from the statements above?
(A) In the city with the worst air pollution today, the air quality is better than it was 30 years ago.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Dec 2012 LSAT (PT68): Logical Reasoning B